Shimano MT610 12 Speed Double ChainsetPrepared for the steep stuff, the fast stuff as well as the fun stuff, this 12 speed MTB crankset gives you powerful acceleration and smooth shifting operation on every ride. It features a rock-solid forged alloy crank arm construction, which allows it to handle all the abuse that's associated with all-day epics in the mountains. Shimano has also kitted out this model with a HollowTech II integrated bottom bracket design for increased stiffness, efficiency and added durability.Features: Crank Arm Material: Forged Alloy Use: MTB Speed: 2x12 speed Design: 2-piece design Number of Chainrings: 2 Chainrings Included: Yes Chainline: 48.8mm Chainring BCD: 135 / 142mm O.L.D. 4 Arm or 5 Arm: 4 arm Chainring Size: 36/26T Chainring Mount: Direct mount Chain Compatibility: For use with 12 speed HG MTB chains only Is BB Included: HollowTech II integrated bottom bracketPart Numbers: 170mm: FCMT610C66; 175mm: FCMT610E66Technologies: HollowTech II: HollowTech II integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durability. Forged Crank Arms: Forged crank arms rigid whilst being incredibly strong and durable.A 2-year warranty is offered with all Shimano products from Chain Reaction Cycles (3 years on Dura-Ace and XTR products).Buy Shimano Components from Chain Reaction Cycles, the World's Largest Online Bike Store.